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All Incompatible Measurements on Qubits Lead to Multiparticle Bell Nonlocality

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Abstract

Bell nonlocality is a fundamental phenomenon of quantum physics as well as an essential resource for various tasks in quantum information processing. It is known that for the observation of nonlocality the measurements on a quantum system have to be incompatible, but the question of which incompatible measurements are useful, remained open. Here we prove that any set of incompatible measurements on qubits leads to a violation of a suitable Bell inequality in a multiparticle scenario, where all parties perform the same set of measurements. Since there exists incompatible measurements on qubits which do not lead to Bell nonlocality for two particles, our results demonstrate a fundamental difference between two-particle and multiparticle nonlocality, pointing at the superactivation of measurement incompatibility as a resource. In addition, our results imply that measurement incompatibility for qubits can always be certified in a device-independent manner.

Original languageEnglish
Article number200201
Number of pages8
JournalPhysical review letters
Volume134
Issue number20
DOIs
Publication statusPublished - 21 May 2025

ASJC Scopus subject areas

  • General Physics and Astronomy

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